SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa9a2da7bfd68a8698b966bb7586d7daf3776988985472f65da14651cdb3edbd' 
  AND token = 'ZESLIr6vQWwH9+cQF9DECneIE0f9BvyMhwrKcafXnjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}